Process of renovating polishing-plates



Wires stares rarest series.

LOUIS SGHULTE, OF PITTSBURGH, PENNSYLVANIA, ASSIGNOR TO E. I. DU PONT in: NEMOURS & COMPANY, OF WILMINGTON, DELAWARE, A CORPORATION OF DELAWARE.

PROCESS OF RENOVATING POLISHING-PLATES.

No Drawing.

To all whom it may concern:

Be it known that I, LOUIS SoHUL'rE, of Pittsburgh, in the county of Allegheny, and in the State of Pennsylvania, have invented a certain new and useful Improvement in Processes of Renovating Polishing-Plates, and do hereby declare that the following is a full, clear, and exact description thereof.

In the manufacture of sheet material such as pyralin it is customary to finish the surfaces of the sheets by the use of a press having a pair of large flat plates with highly polished surfaces, such that the surfaces of the sheets are pressed into a plane and smooth condition. Such press polishing plates are ordinarily composed of a steel or alloy sheet having a nickel facing, and rolled to suitable gage or thickness.

It is requisite that the surfaces of the plates be plane and highly'polished in order to produce a proper surface upon the pyralin sheets, and to maintain this condition, the "sheets have had to be frequently removed from the press and bufied and polished to remove scratches and irregularities from the same, The result was that the continued refinishing soon removed the nickel facing from the plates to such an extent that further use of them was no longer possible, so that the expense of replacing such plates was a large item in the cost of manufacture of the pyralin.

I have discovered that, by the use of proper operations and a suitable nickel plating solution, it is possible to deposit nickel upon the worn surface of the plates in such a way as to fill the depressions therein, so that the plate may be renovated to a plane and polished condition without unduly decreasing the thicknessof the nickel facing, so that the life of the plate will be correspondingly prolonged.

The worn plates are passed through a bufiing machine in which operation the effect of the bufiing roller upon the plate shows up veryclearly any scratches or depressions in the plate surface. If such-depressions appear, a narrow bufiing wheel is used to remove enough material to eradicate the same. The plate is then placed in a cleaning bath, after which it is rinsed or washed, in order to prepare it for the nickel plating operation.

Specification of Letters Patent.

Patented Apr. 5, 1921.

Application filed July 24, 1918. Serial No. 246,532.

In order to fill the depressions in the plate surface any solution suitable for depositing nickel upon nickel may be used. For instance, I may employ a solution of the following character Per cent.

Sulfate of nickel 17 Nickel sulfate and ammonia" 1. 4-. Sodium sulfate 8. 5 Acetic acid"; 2. 1

Water 70. 9

smoothed and polished in the usual manner.

I have foundthat the nickel plated surface of the plates, produced as above described, is as satisfactory as the renovated surface which formerly was brought about solely by buffing away the original nickel facing, and, by my process it is possible to use the same plates for a much greater length of time than has heretofore been the case.

While I have described in detail a process by which such plates may be renovated, it is obvious that many changes may be made without departing from the principle of the invention, as defined in the following claims.

I claim- 1. The process of renovating press polishing plates having a nickel facing, which comprises nickel plating the worn facing by sodium, and single and double nickel salts, and polishing the nickel plated surface.

2. The process of renovating press polishing plates having a nickel facing, which comprises nickel plating the worn facing by means of a solution containing approxlmately 8% sulfate of sodium, 15-20% sulfate of nickel, and relatively small percentages of sulfate of nickel and ammonia and a weak acid, and polishing the nickel plated surface.

In testimony that I claim the foregolng I have hereunto set my hand.

LOUIS SCHULTE.

means of a solution containing sulfate of p 

